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Current Trends Human T-Lynphotropic Virus Type III/
Lymphadenopathy-Associated Virus Antibody Prevalence in U.S.
Military Recruit Applicants
From October 1, 1985, through March 31, 1986, as part of
medical
evaluation of individuals volunteering for military service, the
U.S.
Department of Defense tested 308,076 recruit applicants for
serologic
evidence of infection with human T-lymphotropic virus type
III/lymphadenopathy-associated virus (HTLV-III/LAV), the etiologic
retrovirus of acquired immunodeficiency syndrome (AIDS).* Blood
samples were obtained at 71 Military Entrance Processing Stations.
The screened population consisted predominately of young adults in
their late teens (54%) and early twenties (33% were 20-25 years
old).
Eighty-five percent were male, and 77% were white. Sera were
tested
by a single contracting laboratory using a commercial human
T-lymphotropic virus type III (HTLV-III) enzyme-linked
immunosorbent
assay (ELISA) test (Electronucleonics, Inc.). All samples
repeatably
reactive by ELISA were also subjected to confirmation testing by
the
Western blot. Blots were considered positive if antibodies to gp
41
and/or p24+p55 were detected. Recruit applicants with confirmed
HTLV-III/LAV antibody are excluded from military service.
The mean prevalence of confirmed positive tests was 1.5 per
1,000
recruit applicants. Antibody prevalence increased progressively
with
age (Table 1), a pattern consistent throughout the country (Table
2).
The seroprevalence was higher among the 265,361 men of all ages,
1.6/1,000, than among the 42,715 women, 0.6/1,000. The ratio of
male-to-female prevalence rates was 3:1. Prevalence also varied by
race: for the 237,586 whites, the rate was 0.9/1,000; for the
55,185
blacks, 3.9/1,000; and for the 15,305 applicants of other racial
groups, 2.6/1,000. The relationships of seroprevalence rates by
sex
and race remain when the data are adjusted by age.
Seroprevalence rates (Table 2) were highest in the coastal
regions
of the country other than New England. Rates were lowest in New
England and in the inland regions. Based on preliminary analysis
by
county, the highest HTLV-III antibody rates were found in recruit
applicants from major urban centers and lowest in those from rural
areas.
Reported by the Health Studies Task Force, Office of the Assistant
Secretary of Defense (Health Affairs); Dept of Virus Disease, Div
of
Preventive Medicine, Walter Reed Army Institute of Research;
Surveillance and Evaluation Br, AIDS Program, Center for Infectious
Disease, CDC. Editorial Note
Editorial Note: Although there is considerable knowledge regarding
the
distribution of reported cases of AIDS in the United States (1),
there
has been much less information about the prevalence of infection
with
HTLV-III/LAV. Studies of HTLV-III/LAV antibody prevalence have
primarily involved selected high-risk groups, including homosexual
men
(24%-68% positive) (2-5), intravenous (IV) drug abusers (2%-72%
positive) (6-8), and hemophilia patients (40%-88% positive) (9-11).
The limited published data from blood-bank screening programs,
where
persons in high-risk groups are specifically discouraged from
donating, indicate a confirmed antibody prevalence nationally of
less
than 0.4/1,000 (12).
The Department of Defense medical evaluation program provides
additional information on the geographic and demographic factors
associated with HTLV-III/LAV infection in the United States. The
population of individuals volunteering for military service may not
be
representative of the U.S. population at large due to the
spontaneous,
if partial, self-exclusion of hemophilia patients, actively
homosexual
men, and current IV drug abusers. However, the data suggest the
following: (1) While the highest seroprevalence occurs among those
over 25 years old, the age of acquisition of confirmed antibody
(and
by implication, infection) can often be in the late teens and early
twenties. Age at diagnosis of reported AIDS is older, with a
median
of 32-35 years, depending on risk group, race, and sex. Only 0.7%
of
reported cases among adults/adolescents occur between 13 and 20
years
of age; 6.5% develop between 21 and 25 years; the remaining 92.8%
are
diagnosed at or after 26 years of age. (2) The ratio of
seroprevalence between male and female recruit applicants is 3:1.
This is much lower than the ratio of 13:1 observed among all AIDS
cases, but like the 3:1 ratio among other AIDS patients if
homosexual
and hemophilia-associated cases are excluded. (3) The ratio of
seroprevalence rates of black to white recruit applicants (4:1) is
intermediate between the 2.6 relative risk for blacks among all
AIDS
patients (25.2% of cases are among non-Hispanic blacks, who
comprise
11.5% of the population (13)) and the 8.3 relative risk for blacks
among AIDS patients not associated with either homosexuality or
hemophilia (blacks comprise 52.0% of these cases). The data do not
yet permit a detailed analysis of seroprevalence differences by
Hispanic ethnicity. (4) The geographic distribution of
seroprevalence
among recruits is generally consistent with the incidence of cases,
both by region and by urban versus rural residence. More detailed
geographic analysis will be possible when cumulative data are
available from screening additional recruits.
As in the case with serologically positive blood donors (14),
recruit applicants with confirmed positive antibody are informed of
their status and its implication regarding infection with
HTLV-III/LAV; they are counseled on reducing the risk of
transmission
to others through sexual contact, sharing IV needles, or other
exchanges of blood or body fluids.
Counselling and testing for HTLV-III/LAV antibody should be
offered to persons who may have already been infected as a result
of
intimate contact with the seropositive recruit applicant (i.e.,
sexual
partners, persons with whom needles have been shared, infants born
to
seropositive mothers). In addition, seropositive individuals
should
be interviewed by an experienced investigator to determine their
risk
factors for infection. This, coupled with observation on suitable
controls, would facilitate determining modes of acquisition and
evaluating current trends in risk of exposure to the virus in these
populations.
The continued analysis of data emerging from the HTLV-III/LAV
serologic screening of military recruit applicants will permit the
examination of the extent and the trends over time of infection
with
the causative agent of AIDS in this sentinel population.
References
Peterman TA, Drotman DP, Curran JW. Epidemiology of the
acquired
immunodeficiency syndrome (AIDS). Epidemiol Rev 1985;7:1-21.
Phair J. Prevalence and correlates of HTLV-III antibodies
among
5000 gay men in 4 cities. Multicenter AIDS Cohort Study (MACS)
(Abstract). 25th Interscience Conference on Antimicrobial
Agents
and Chemotherapy. Minneapolis: America Society for
Microbiology,
1985:229.
Collier AC, Barnes RC, Handsfield HH. Prevalence of antibody
to
LAV/HTLV-III among homosexual men in Seattle. Am J Public
Health
1986;76:564-5.
Schwartz K, Visscher BR, Detels R, Taylor J, Nishanian P, Fahey
JL. Immunological changes in lymphadenopathy virus positive
and
negative symptomless male homosexuals: two years of
observation
(Letter). Lancet 1985;II:831-2.
Darrow WW, Jaffe HW, O'Malley PM, et al. Sexual practices and
HTLV-III/LAV infections in a cohort of homosexual male clinic
patients, San Francisco (Abstract). 6th International Meeting
of
the International Society for STD Research. Brighton:
International Society for STD Research, 1985:31.
Levy N, Carlson JR, Hinrichs S, Lerche N, Schenker M, Gardner
MB.
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drug
users attending treatment programs in California: a
preliminary
report (Letter). N Engl J Med 1986;314:446.
Weiss SH, Ginzburg HM, Goedert JJ, et al. Risk for HTLV-III
exposure and AIDS among parenteral drug abusers in New Jersey
(Abstract). Atlanta: International Conference on Acquired
Immunodeficiency Syndrome (AIDS), 1985:44.
Spira TJ, DesJarlais DC, Bokos D, et al. HTLV-III/LAV
antibodies
in intravenous drug (IV) abusers--comparison of high and low
risk
areas for AIDS (Abstract). Atlanta: International Conference
on
Acquired Immunodeficiency Syndrome (AIDS), 1985:84.
Ragni MV, Tegtmeier GE, Handwerk-Leber C, Lewis, JH, Mayer WL,
Spero JA. Prevalence and seroconversion of human
T-lymphotropic
retrovirus (HTLV-III) antibody in patients with hemophilia
(Abstract). Atlanta: International Conference on Acquired
Immunodeficiency Syndrome (AIDS), 1985:74.
Jason J. McDougal JS, Holman RC, et al. Human T-lymphotropic
retrovirus type III/lymphadenopathy-associated virus antibody.
Association with hemophiliacs' immune status and blood
component
usage. JAMA 1985;253:3409-15.
Goedert JJ, Sarngadharan MG, Eyster ME, et al. Antibodies
reactive with human T cell leukemia viruses in the serum of
hemophiliacs receiving factor VIII concentrate. Blood
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Schorr JB, Berkowitz A, Cumming PD, Katz AJ, Sandler SG.
Prevalence of HTLV-III antibody in American blood donors
(Letter). N Engl J Med 1985;313:384-5.
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